Plenum chamber



H. J. CHADWICIK PLENUM CHAMBER Filed Aug. 10, 1951 United States Patent PLENUM CHAMBER Hamilton J. Chadwick, St. Clair Shores, Mich., assignor to Woodall Industries Inc., Detroit, Mich a corporation of Michigan Application August 10, 1951, Serial No. 241,275 Claims. (Cl. -05) This invention relates to improvements in plenum chambers such as are used in motor vehicles and may be disposed to extend along the fire wall or dash assembly that separates the engine compartment from the passenger compartment and to fastener spacer devices used in fabricating such chambers.

Such a chamber may receive hot .or cool air from suitable sources which 'air maybe distributed from the chamber by means provided therefor for heating or cooling purposes. Such a chamber may be formed of deformable self-sustaining sheet material secured together by fastener spacer elements of improved design. Such fastener spacer elements are so constructed as to secure opposed margins of the sheet material together in spaced relationship, and so constructed as to be capable of engaging the sheet material to secure the same spaced apart without the aid of supplemental fastener means.

An object is to provide a plenum chamber of this character with improved fastener spacer elements which serve to secure opposed walls of the chamber together in a desired spaced relationship.

Such improved fastener spacer element is so constructed and secured in place between the opposed walls of the chamber as to fasten such walls together 'and also to hold them in desired spaced apart relationship. The

element functions effectively to accomplish both purposes.

It :also occupies a minimum amount of space and therefore does not appreciably obstruct the flow or passage of .air from within the chamber through the space between opposed marginal areas thereof. In its preferred form it .serves in and of itself to accomplish such results.

.In this improved plenum chamber the fastener spacer elements which secure opposite marginal areas of the side walls together in determined spaced relation serve to provide a plenum chamber, which is inexpensive and simple, which functions effectively to serve its .intended purpose, and wherein the spacer elements themselves employ a minimum amount of material and are easily and quickly installed in place.

A plenum chamber of the character herein disclosed is so constructed as to present areas of varying hollow dimension and spacing of side walls. One wall of the chamber may be shaped to exhibit a contour substantially different from that of the cooperating opposite Wall. It may present a series of elevations and depressions throughout certain areas which increase and diminish the space between the two Walls. Opposed margins of the two may be closely fastened together throughout certain marginal areas while throughout other areas the margins of the two walls will be held in spaced relationship by fastener spacer elements which serve to fasten them together and at the same time hold them spaced apart.

Various advantages, objects and features of the instant invention will be brought out in the following specification, claims and accompanying drawing, wherein:

Fig. l is a perspective of a plenum chamber defining the invention;

the line 3-3 of Fig. 1;

Fig. 4 is a cross sectional view taken on the line 4-94 of Fig. 3;

Fig. 5 is a cross sectional view taken on the line 55 of Fig. 3;

Fig. 6 is a perspective of a spacer fastener element such as is used and such as is shown in the other figures of the drawing 1 through 5;

Fig. 7 is a perspective of a spacer fastener element of a modified form as compared with that of Fig. 6;

Fig. 8 is a cross sectional view similar to Fig. 5 showing the fastener of Fig. 7;

Fig. 9 is a detailed view of the top portion of Fig. .8 showing the method of fastening the spacer to the fiberboard.

Plenum chambers of the character herein shown are in common use in motor vehicles. Sueh chambers are generally disposed adjacent the dash assembly a d may be supported thereby. Such chambers exhibit hollow areas of various dimension and are provided with intake and outlet openings. They are adapted to receive heated air from a suitable heater and are commonly provided with ducts communicating with cooling air. Ducts also lead from the chamber to distribute hot or cold air, as the case may be. The duct arrangement and communication with sources of air has nothing to do with the instant invention.

1' t is common practice to provide a chamber of this type vof material which is inexpensive and yet will serve the purpose of an air chamber. Such material can also be readily deformed and will retain a deformed shape so as to make up a hollow chamber-like structure. One type of material which is in common use is a composition asphalt impregnated fiberboard such as sold under the trade name of K-B board. This type ofmaterial may be shaped in a press to exhibit the deformations which facilitate the provision of hollow spaces between two such pieces of board secured together along their margins.

In the drawings such a chamber is shown in Fig. 1. This figure illustrates an elongated structure having opposed side walls 10 and 12. These two side wall portions are shaped to fit together to provide a hollow structure and are secured together throughout a certain ma ginal area by staples 14. Throughout such marginal area the .a series of deformations such as are illustrated wherein tcertain areas of the sheet are -spread-away from the opposite sheet. These deformed areas provide also the marginal areas of sheet 12 which normally are spaced away from the opposed marginal area of sheet 10, as for example, at points 16 and 18. Throughout these marginal areas of spaced relationship the two side walls are held together by fastener spacer elements which serve to hold the two side walls together and also serve to hold them in determined spaced relation.

These fastener spacer elements are so formed as to hold the opposite side walls securely in determined spaced relationship. One of such elements is illustrated in Fig. 6. It is a U-shaped element having a base portion 20 and two leg portions 22. Each leg portion has its outer end bent at a right angle to the plane of the leg to provide a foot 24. Each foot 24 is shaped to exhibit at opposite ends two tangs or prongs 26. These tangs are bent through a side wall of the sheet material as shown in Figs. 4 and 5 and clenched thereover as at 28 so as to securely fasten said side wall to the legs of the fastener spacer element.

The opposite side wall of the plenum chamber may be secured by wire stitching or a staple 30 to the crown or base 20 of the fastener spacer element as shown particularly in Fig. 4. The base of the fastener spacer element is provided with an aperture 21 as shown in Fig. 6. It will be noted that when the staple or wire stitch 30 has been inserted to secure the base of the fastener to the adjacent side wall that the ends of this staple are bent into the aperture 21 so as to be entirely out of the way and to conceal the pointed ends of the staple.

It will be seen that these fastener spacers serve to effectively hold the side walls together while also spacing them a desired distance apart. They occupy a minimum amount of space so that the passageway for air between the spaced margins of the side walls is relatively unobstructed thereby. The fastener spacer elements may be easily installed in machines provided for that purpose and such operation may be quickly carried out.

Fig. 7 illustrates a modified and preferred form of fastener as compared with that of Fig. 6. It varies therefrom in that it is entirely self-contained. It does not require supplemental means to secure it to the sheet material. In the fastener of Fig. 7 the base 20 of the fastener is provided with tangs 32 formed from the material of the fastener. These tangs are adapted to be received through one side wall of the plenum chamber in lieu of the wire stitching 30. These tangs are shown in Fig. 7 as elevated to be projected through the fiberboard. These tangs are designed to be received and clenched into the sheet material as shown in Figs. 8 and 9. These tanks are not embedded within the sheet material. This modification is also provided with feet portions 24 themselves provided with tangs 26, as is the fastener of Fig. 6. However such tangs 26 may likewise be embedded within the sheet material.

What I claim is:

1. A spacer fastener of a U shape wherein the two legs of the U have a length not less than the length of the base and wherein each leg has its end portion bent outwardly at a right angle with respect to the plane of the leg forming the foot, opposite ends of the foot provided with tangs projecting outwardly therebeyond and adapted to be bent over to clench through material to secure the foot thereto.

2. A spacer fastener of a U shape wherein the two legs of the U have a length not less than the length of the base and wherein each leg has its end portion bent outwardly at a right angle with respect to the plane of the leg forming the foot, opposite ends of the foot provided with tangs projecting outwardly therebeyond and adapted to be bent over to clench through material to secure the foot thereto, the base of the U provided with an aperture therethrough spaced substantially midway between the two legs of the U.

3. A spacer fastener of a U shape wherein the two legs of the U have a length not less than the length of the base and wherein each leg has its end portion bent outwardly at a right angle with respect to the plane of the leg forming the foot, opposite ends of the foot provided with tangs projecting outwardly therebeyond and adapted to be bent over to clench through material to secure the foot thereto, the base of the U provided with spaced tangs adapted to be projected through material and bent thereover to secure the base thereto.

4. In a chamber having opposed side walls secured together throughout a certain area in spaced relationship, a plurality of U-shaped spacer fastener elements interposed between the walls within said area, each fastener element having the base of its U secured to one wall by a prong punched out of the base and extended through the wall and clinched over against that surface opposite the base, the two legs of the U-shaped spacer fastener extending from the base toward the other wall with each leg provided at its extremity with a foot portion bent at substantially right angles to the leg and abutting the surface of the wall, each foot portion shaped to provide a tang which extends substantially perpendicularly away from the foot and projects through the wall with the tip of the tang folded over upon and clinched against the opposite surface of the wall to grip the wall between the foot portion and the tip of the tang securing the walls together through the fasteners and spaced apart by the fasteners.

5. A plenum chamber having opposed side walls secured together throughout one marginal area by fasteners having portions extending through the walls securing them together in closely abutting relationship, said walls being secured together throughout another marginal area by U- shaped fasteners disposed between the walls at intervals, each fastener having the base of the U shape bearing against the inner surface of one wall and having the two legs of the U shape terminating in angularly disposed feet bearing against the inner surface of the other wall spacing said walls apart, said feet having portions extending through said other wall and clenched thereover holding the wall against the feet, said base having connecting means extending through its wall securing the wall thereagainst.

References Cited in the tile of this patent UNITED STATES PATENTS 860,341 Stimpson July 16, 1907 1,597,227 Wright Aug. 24, 1926 1,655,082 Armstrong Jan. 3, 1928 1,933,035 Swift Oct. 31, 1933 2,116,020 Gauvin May 3, 1938 2,268,517 Small Dec. 30, 1941 2,300,449 Rowe Nov. 3, 1942 2,306,796 Staley et al. Dec. 29, 1942 2,409,262 Eldred Oct. 15, 1946 2,417,423 Lang Mar. 18, 1947 2,558,132 Green June 26, 1951 

